As stated in the Controller
interface, a lot of functionality is already provided by certain abstract
base controllers. The AbstractController is one of the most important
abstract base controller providing basic features such as the generation
of caching headers and the enabling or disabling of
supported methods (GET/POST).

Inspection of supported methods (ServletException if request method
is not support)

If session is required, try to get it (ServletException if not found)

Set caching headers if needed according to the cacheSeconds property

Call abstract method handleRequestInternal()
(optionally synchronizing around the call on the HttpSession),
which should be implemented by extending classes to provide actual
functionality to return ModelAndView objects.

comma-separated (CSV) list of methods supported by this controller,
such as GET, POST and PUT

requireSession

false

whether a session should be required for requests to be able to
be handled by this controller. This ensures that derived controller
can - without fear of null pointers - call request.getSession() to
retrieve a session. If no session can be found while processing
the request, a ServletException will be thrown

cacheSeconds

-1

indicates the amount of seconds to include in the cache header
for the response following on this request. 0 (zero) will include
headers for no caching at all, -1 (the default) will not generate
any headers and any positive number will generate headers
that state the amount indicated as seconds to cache the content

synchronizeOnSession

false

whether the call to handleRequestInternal should be
synchronized around the HttpSession, to serialize invocations
from the same client. No effect if there is no HttpSession.

Constructor Detail

AbstractController

Method Detail

setSynchronizeOnSession

public final void setSynchronizeOnSession(boolean synchronizeOnSession)

Set if controller execution should be synchronized on the session,
to serialize parallel invocations from the same client.

More specifically, the execution of the handleRequestInternal
method will get synchronized if this flag is "true". The best available
session mutex will be used for the synchronization; ideally, this will
be a mutex exposed by HttpSessionMutexListener.

The session mutex is guaranteed to be the same object during
the entire lifetime of the session, available under the key defined
by the SESSION_MUTEX_ATTRIBUTE constant. It serves as a
safe reference to synchronize on for locking on the current session.

In many cases, the HttpSession reference itself is a safe mutex
as well, since it will always be the same object reference for the
same active logical session. However, this is not guaranteed across
different servlet containers; the only 100% safe way is a session mutex.

handleRequest

Process the request and return a ModelAndView object which the DispatcherServlet
will render. A null return value is not an error: It indicates that
this object completed request processing itself, thus there is no ModelAndView
to render.